Hot top



Oct. 18, 1938. w, B O DEN 2,133,829

' HOT TOP Filed NOV. 20., 1955 IN VENT OR.

M4 roRNEYs Patented Oct. 18, 1938 UNITED STATES 2,133,829 HOT TOP William B. Ogden, Youngstown,

Ohio, assignor to Valley Mould &- Iron Corporation, Hubbard, Ohio, a corporation of New York Application November 20, 1935, Serial No.. Q,639

1 6 Claims.

The present invention relates to metallurgy and more particularly to hot tops, for ingot molds, commonly used in the production of certain types of high quality steel.

A hot topis a construction, usually separate from an ingot mold, which is a heat insulated device comprising an extension of the upper end of the mold cavity. The hot top contains molten steel when the mold is filled and because of its insulating character will retain a supply of molten steel above the matrix of the ingot mold while the ingot is freezing in the mold so that molten steel may be supplied to the freezing ingot to fill cavities therein which otherwise would form as the steel freezes, and which are known in the art as pipes.

In general there are two general types of hot tops, those which are intended for use only once, and are replaced for each set up of the mold each time an ingot is cast in the mold, and those which are of a more permanent nature so that a single hot top may be used to cast several ingots. The present invention belongs to the latter type.

It is desirable that the joint between the hot top and the mold shall be of such character as to prevent the molten steel from running into the joint opening and forming fins which will interfere with the stripping of the ingot from the mold. One construction which obviates this difliculty is a hot top provided with a cast iron base plate which forms a metal to metal contact with the end of the mold, as disclosed in Ramage Patent No. 1,792,868. In order to maintain the metal to metal joint in its most effective relation 35 to the ingot mold, it is desirable that the inner edge of the hot top base plate shall come into contact with the molten steel. The base plate of the hot top is preferably formed of cast iron and when it comes in contact with the molten steel, the inner edge of the base plate becomes much more highly heated than the outside edge. This unequal heating of the hot top base plates causes distortion which usually results in warping that sooner or later becomes permanent and thereby provides a very uneven bearing surface that contacts with the end of the mold. The result of this uneven bearing surface is'that the joint between the mold and the base plateopens up sufliciently in various places to cause the formation of fins.

One of the factors which causes the warping of heating of the inner edge expands the metal adjacent the inner'edge but the outer portion does not expand since it is cold. The expansion of the metal adjacent theinner edge places that portion of the base plate under compression and the outer edge under tension. This bends and warps thebase plate out of the normal flat plane. It also tends to cause a condition adjacent the inner edge known as growth whereby the base plate tends to become thicker wat the inner edge and consequently distorted out of normal plane.

The present invention overcomes the difficulties of the known prior art by providing a construction wherein slots are cut through the inner edge to provide sufiicient clearance between sections of the inner edge of the base plate so that this edge may expand linearly without causin severe compression forces to be set up. Since these inner edge portions of the base plateImay now expand freely, the base plate does not warp and the tendency for the base plate to grow is eliminated. V

The present invention may be carried out in various ways, but preferably, comprises the severing of the inner edge of the baseplate by slots or complete severance joints so that portions of the inner edge may expand without establishing compression-at the inner edge andtension at the outer edges 1 l.

It is recognizedthat the present invention may be embodied in structures other than those specifically disclosed herewith s0, therefore, the disclosure is to be understood as illustrative and not in the limiting sense. j

I 'Fig. 1 illustrates a hot'top in accordance with the present invention on'the upper end of an ingot mold, and showing a portion of the mold and the hot top in vertical section.

Fig. 2 is a plan View of a base plate for a hot top in accordance with the present invention and showing slots cut through the base plate at its inner edge adjacent the corners of a substantially rectangular base plate.

Fig. 3 is a plan view of a base plate fora hot top showing slots at the corners and at the mid portions of-ithe sides thereof.

.Fig. 4 illustrates a base plate for a hot top made of four separate parts with the separation of the parts occurring at the middle of the sides of the plate. v

Fig. 5 illustrates a base plate for ahot top made of four separate pieces with the separation occurring at the corners of the base plate.

Referring to the drawing and more especially to Fig. 1, an ingot mold l is provided on its upper end with a plane surface 2 thatforms a metal to metal joint with a hot top base plate 4. This base plate is preferably formed with a brick supporting surface 5 against which refractory brick 6 set. A shell or casing l surrounds and supports the refractory brick 6 and this shell is preferably provided with lugs 8 adapted to receive a crane hook for manipulating the hot top into position over the mold. The upper end of the hot top comprises a separate cover plate 9 which sets over the shell or casing I and extends over the upper ends of the bricks G to protect and support the same within the shell. The bottom plate 4 preferably is secured to the shell or casing 1 by means of bolts H] which pass through the bottom plate and suitable lugs on the side of the shell-or casing I. The cover platei! is=also attached toithe shell or casing by means of bolts I l which likewise pass through suitable lugs on the casing and on the top plate. Preferably, the sides of the casing 1 are provided with lugs l2 and the upper'en'd of the mold with adjacent lugs l4. Both of these lugs 12 and 'l4aredrilledto provide an opening for guide pins I 5 carried bythe 'hot top casing and which definitely position the hottop on the mold.

Referringto Fig. 2, which-is a plan view of the base plate 4, this baseiplate'is slotted at the corners by'slots l'5'which sever the inner edge of the base plate and extend outwardly beyond brick supporting surface 5 with the outer edge of the base plate 3 'unsevered. These slots, therefore, are spaces into which the ends of the sides of thebase plate 4 may expand when this inner edge becomes heated. Preferably, the slots l5are of sufficient width to be sure to accommodate the greatest amount of expansion that will occur in the inner edges of the base plate. 'These slots mayvary in width from one-eighth to one-quarter inch. 7

Fig. 3 illustrates a baseplate 4 similar to that shown in Fig.2 with the exception that additional slots l6 are provided in the sides of the base plate and these slots preferably terminate in drill holes H. Thepurpose of .theseslots is exactly the same as the purpose of \the slots 15 described with reference to'Fig. '2.

Fig. 4 illustrates .a slightly different construction in which the four sidesof the-base plate are completely severed to comprise joints .l-.8;and in such manner that the base .plate 4 is made up of four separate sections. These-separate sections consequently are free to expand and move slightly when the :inner edge-of the base plate is heated. r a

Fig. 5 is-a-construction similar tothatdisclosed in .Fig. 4 with the exception-that the joints separating the four pieces of the base plate occur at the corners of asquare matrix type of base plate. This base plate illustrated :in Fig. 5 is likewise made up of fourpieces each of 'whichis completely separate 'or separatedfrom 'its'neighbor'to provide an iexpansion'j'oint 1.9 into whichthe inner sides may expand.

. When the hot top of the present invention is placed in position -on'the mold, slurry is used to coat the entire inner surface of the hot top and all'joints that occur. This slurry, therefore, tends to seal the joints between the mold and the hot top andalsobetween the base plate and the .refractory bricklining. Likewise the slurry-tends to fill'up'the ends of the saw cuts or slots at the inner "edge of "the base plate, thereby .preventing molten 's'teel from flowing in these slots or cuts and forming 'fins which might interfere with thestripping of "the ingot.

A practical use of the present hot top shows that the construction comprising the slots or open joints between sections of the base plate prevents warping and cracking of the base plate and also prevents the base plate from growing or becoming distorted due to the differential heating of the base plate while in use.

What I claim is:

1. -A hoti-top 'foringot m'olds comprising a casing, a refractory -lining within said casing, and a metallic base plate adapted to contact with the upper end of an ingot mold and capable of expansion and contraction independently of said casing, said base plate having a centrally located openingand'with slots extending outwardly from the edge 'of said'opening and comprises spaces to permit -.expansion .o'f the inner edge of said base plate when the inner edge of said base plate is heated by molten steel while the hot top is in use, said'refractory lining contacting with one side of said base plate and ingot mold metal contacting-with -the oppositeside of said base plate.

2. A'hot'tcp "for'ing'o't molds comprising a supporting member, a refractory lining supported by said supportingmember,'a'cast ironbase plate having a matrix opening therein and adapted to contact'in a'metal to'metal'joint with the upper end of a'm'etallic 'ingot'm'old, the'inner edge of said base'plate beingincontactwithmolten steel when saidmold and hot top arefilled to cast an ingot, said'base plate 'havingslots extending outwardly from the'inn'er edge of saidmatrix opening'in said bas'eplate, said slotsbeing adapted to permit the expansion of the inner edge of said base plate'without'distortion when the inner edge of said-base plate is 'heat'ed'by molten steel while said hot top is in use, said refractory'lining contacting with one .side of said baseplate and ingot mold metal "contacting 'with the-opposite side of said base plate.

3. In a 'hot top for ingot molds comprising .a continuation .of thematrix opening of an ingot mold to 'containmolten steel at alevel above the matrix of the mold, the improvement consisting of a metallic base 'platefor said hot top, said base plate being adapted to be seated on .the upper end of an ingot mold and having a centrally located opening and with the inner edge thereof separated 'into sections to permit the expansion ofthe metal adjacent the inner edge of the base plate when said inner edge is heated by molten steel while'the hot top is in use, heat insulating material in contact with one-side of said base plate, and chilling metal on the-opposite side of said base plate.

4. An article of manufacture comprising a metallic base plate for a hot top, said baseplate being provided with a centrally located substantially'rectangular opening and with the edges of said opening being vseparated'into sections at the corners of said rectangular opening whereby the metal adjacent the inner side edges of the base plate may expand without distortion and warping, heat insulating material'in contact with one side of said base plate and chilling metal on the opposite side -0f said 'baseplate.

'5. An article of manufacture comprising a cast iron base plate for a'hot'top, said base plate being provided with a centrally located opening, the edge of which is adapted to come into contact with molten steel when .thebase plate -is-in use, the said edge being separated into sections which are spaced apart sufliciently to permitexpansion of the inneredge of said base plate, heat insulatingLmaterial-incontact with one side of said base plate and chilling metal on the opposite side of said base plate.

6. An article of manufacture, a metallic base plate for hot tops adapted to form a metal to metal joint with the upper end of a metallic ingot mold, said base plate being provided with a central opening, the edge of which is adapted to contact with molten metal when said base plate is in operation with the upper face of said base plate in contact with heat insulating material and the lower face of said base plate in contact with the metal of an ingot mold, the said edge of said base plate being divided into sections which are spaced apart sufliciently to permit expansion of each individual section without imposing compression forces upon an adjoining section.

WILLIAM B. OGDEN. 

